As for pubic and underarm hair, Lasasi considers it could be a so-called eardrum – a byproduct of the evolution of another feature – or potentially a remnant of primate ancestors who used pheromones to communicate with each other (there is no good evidence that humans use pheromones today).
Whatever caused the loss of human fur, one thing is extremely likely: it coincided with early humans acquiring darker skin pigmentation when body hair would previously have been a necessary protection against UV rays.
“That’s the logical inference we can make,” Lasasi says. “It could be that some humans ended up being born with completely hairless bodies and then it became an adaptation in tandem with some of those humans evolving with darker skin. Or it could be that there was a reduction slightly more gradual hair growth that was occurs with a slightly more gradual increase in skin pigmentation.”
While it’s interesting to examine how we lost our fur, it may seem less relevant to our lives today. But research has indicated that a better understanding could even have implications for people suffering from unwanted hair loss today due to baldness, chemotherapy or disorders causing hair loss.
In early 2023, Nathan Clark, a geneticist at the University of Utah, and his colleagues Amanda Kowalczyk and Maria Chikina at the University of Pittsburgh, studied the genes of 62 mammals, including humans, to find the genetic changes that hairless mammals shared among themselves. excluding their furry cousins. They found that humans seemed to have the genes for a full coat of hair, but our genome regulation currently prevents them from expressing themselves.
They also discovered that when a species sheds its hair, it does so by altering the same set of genes over and over, and discovered several new genes involved in this process.
“Some of these [new] the genes hadn’t really been characterized at all, because people hadn’t done a lot of genetic screens for the presence and absence of hair in the past,” Clark explains.[They] seem like maybe master controllers that could be manipulated in the future if people wanted to stimulate hair growth.”
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